Hydraulic valve actuating mechanism



R. SMILTNEEK `HYDRAULIC VALVE ACTUATING MECHANISM April s, 195s Filed Aug. 50, 1954 2,829,628 Patented Apr. 8, 1958 United States Patent @thee HYDRAULIC VALVE ACTUATING MECHANISM Ralmond Smiltneek, Milwaukee, Wis., assignor to Nordberg Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application August 30, 1954, Serial No. 452,848 12 Claims. (Cl. 1215-90) `This invention is in the field of hydraulic valve actuating mechanism usable on internal combustion engines or the like, although it is not limited in this respect.

A primary object of my invention is a hydraulic valve actuating mechanism which is adapted to return a substantial portion of the energy stored in the valve spring to the cam shaft.

Another object is a hydraulic valve mechanism which is adapted to be adjusted so -that the timing of the valve can be tied to and changed in accordance with any variable engine factor, such as load, speed, or the like.

Another object is an engine valve actuating mechanism which does not require any cumbersome mechanical linkages.

Another object is an engine valve actuating mechanism which is adapted to be adjusted to change either the time of closing or the time of opening of the valve, or both, in accordance with a variable engine factor.

Another object is a valve mechanism of the above type which can be arranged to vary both the time oi' opening and closing of the Valve without changing Ithe time that the valve is open and closed.

Other objects will appear from time to time in the ensuing speciication and drawing in which I have diagram matically illustrated the preferred form of my invention.

Figure l shows the mechanism with the valve closed;

Figure 2 shows the position of the mechanism as the valve begins to open;

Figure 3 shows the mechanism with the valve fully open;

Figure 4 shows the mechanism as the valve closes; and

Figure 5 shows the mechanism with the valve fully closed returning to the position of Figure l.

Considering for the moment only Figure l, a conventional engine cylinder of any type is indicated generally at and includes a port l2 controlled by a valve 14 having the usual stem le. A cylinder 18, with a piston 20 connected to the stem of the valve, is used to open and close the valve. `The usual valve closing spring 22 bears against the wall of the cylinder and the piston.

A source of hydraulic Huid is indicated at 24 in communication with a hydraulic system, which includes a suitable reservoir 26 leading through two branches 28 and 30 to a hydraulic line 32, which communicates with the cylinder 18. The branches have cylinders 34 and 36 and pistons 3S and 4i) respectively. The cylinder 34 has a suitable port 42 which `communicates with the reservoir chamber 26, While the other cylinder has a similar port 44, which also communicates with the reservoir.

The pistons carry follower rollers 46 and 48 which bear against a cam 50 on the engines conventional cam shaft 52.

The use, operation and function of my invention are as follows:

l provide a simple, yet reliable, hydraulic valve actuating mechanism which accurately opens and closes, in any desired timed relationship, the valve of any type of engine.

follower cylinders and pistons,

The valve can be a gas valve, an air valve, or any type of liquid valve for that matter, although it is presently intended to be used as either an air inlet or exhaust valve on an internal combustion engine.

ln Figure 1 the valve is closed with the cam shaft rotating counterclockwise, as indicated by the arrow. The piston 4t) is a Valve closing piston, while the piston 38 is a valve opening piston. ln Figure l, both of the pistons are in the down position and their follower rollers are riding on the base circle of the cam 50.

ln Figure 2, the cam shaft has rotated counterclockwise until the cam 5ll has lifted the piston 40 so that it closes its ports 44. The upward movement of the piston 40 displaces the uid in the system, as shown by the arrows, through the cylinder 34 into the reservoir 26 and the valve 14 remains closed. lt should be understood Ithat .the pressure of the hydraulic lluid from the source 24 is less than the force of the spring 22, so that the pressure from the source alone will not open the valve. In Figure 2, the cam is just beginning to lift the opening piston 38.

In Figure 3, the cam shaft has rotated counterclockwise and the piston 38 has been lifted so as to close its ports 42. At the same time, the piston 40 remains elevated and keeps its ports closed. The fluid. is therefore isolated from the reservoir 26 and is trapped in the branches 28 and 30, in the line 32, and the cylinder 18. The upward movement of the piston 38, after it has closed its port 42, will force the valve 14 open.

In Figure 4, I have shown the next step, in which the opening piston 4l) has moved down the cam 50 to again contact the base circle of the cam. This opens the ports 44 and allows the spring 22 to force the fluid. through the pipe 32, branch 30, and cylinder 36 int-o the reservoir. Thus the valve will close at this point.

In Figure 5, l have shown the nex-t stepv in which the closing piston 40 is still in contact with the base circle and the opening piston has started down the cam toward the base circle. This movement will open the ports 42 and the hydraulic fluid ows from the reservoir, in the direction of the arrows, through the cylinder 36, around the branches 30 and 28, into the space behind the opening piston 38.

This completes the sequence of operation of the device and it should be noted that both pistons must be raised to fully close their respective ports before the valve is opened, as in Figure 3. The time of opening the valve is determined by the opening piston 38, while the time of closing the valve is determined by the closing piston 40.

It should be understood that variable timing of the valve could be acquired by varying the angular position of cither one or both of the pistons 38 and 40 by any suitable mechanism. For example, if the opening cylinder and piston were rotated clockwise about the cam shaft, the valve would open earlier, whereas if it were rotated counter-clockwise, the valve would open later. In a like manner, if the closing piston 40 were rotated clockwise, the valve would close earlier while, if it were rotated counter-clockwise, the valve would close later in the engine cycle.

Any suitable well-known mechanism could be used to vary the angular position of either one or both of the depending upon the operation desired. For example, reference is made to United States patent application, Serial No. 415,792, led March 12, 1954, assigned to the assignee of the present application, in which an air inlet valve is variably timed by the engine governor so as to vary in direct relation to the load on the engine. In a similar manner the timing of this valve mechanism could be varied by tying the closing piston 40 to the engine governor, so that the time of closing of the inlet valve would be varied in direct relation to the load.

asesinas As another example, my valve actuating mechanism could be tied to the inlet manifold on a supercharged engine in a manner similar to that shown in U. S. 1ratent 2,670,595, so that the time of closing of the inlet valve would be varied in direct relation to the inlet manifold pressure.

The above examples are given merely to show that many factors and various types of mechanism responsive to these factors on an engine can be used to vary the angular position of either or both of the closing and opening piston, as desired. It should also be understood that the closing and opening pistons could both be moved either clockwise or counter-clockwise together, so that while both the time of opening and closing of the valve would be retarded or advanced, the angular distance between them would remain the same, so that the time that the valve was opened and closed would not change.

An important advantage of my invention is that the movements of the valve will follow the kinematics of the cam profile. Additionally, the device has only three moving parts, the two follower pistons and the valve piston. It has no extra springs, poppet valves, check valves, or the like, and accordingly it is reliable and very seldom gets out of adjustment.

It will be realized that whereas I have described and illustrated a practical and operative device, nevertheless, many changes may be made in the size, shape, arrangement, number and disposition of parts without departing materially from the spirit of my invention. For example an overflow line could be 'provided between the valve cylinder 18 and the source 24 to set the maximum open position of the valve, if desired. I wish, therefore, that my showing be taken as in a large sense illustrative or diagrammatic rather than as limiting me to the precise details of my selected form of illustration.

I claim:

l. In a hydraulic system, a valve with a valve stem, a valve operating cylinder and a piston connected to the stern, a source of high pressure fluid, a line of communication between the source and the cylinder having two branches, a follower cylinder and piston in each branch, means for actuating the following pistons in a predetermined timed relation, and port means in the follower cylinders between the source of uid and the valve operating cylinder and piston opened and closed by the follower pistons.

2. In a hydraulic system, an engine valve, a piston therefor, a source of high pressure lluid, a line of communication between the piston and `the source having two branches leading to the same side of the valve piston, a follower piston in each branch, and means for actuating the follower pistons in a predetermined timed relation.

3. The structure of claim 2 wherein the follower pistons are actuated by the engine camshaft.

4. The structure of claim 3 in which the follower pistons are disposed at an angle with respect to each other in alignment with and actuated by the engine camshaft.

5. In a fluid system for controlling an engine valve, a source of high pressure fluid, an engine valve with an actuating piston thereon, a line of communication between the actuating piston and the source having two branches, a chamber in each branch, a follower piston reciprocally mounted in each chamber, port means in each chamber in the line of communication, said port means being controlled by the follower piston, and a cam shaft with cam means thereon for actuating the follower pistons, the pistons being disposed Iat a predetermined angle with respect to each other.

6. A fluid system for controlling an engine valve including a source of high pressure fluid, an engine valve with an actuating piston therefor, a line of communication between the actuating piston and the source of fluid having two branches, a chamber in each branch, a follower piston reciprocally mounted in each chamber, port means in each chamber in the line of communication Controlled by the piston, a cam shaft with cam means thereon for actuating the follower pistons, the pistons being disposed at a predetermined angle with respect to each other, and spring means for biasing the valve closed against the pressure of the Huid.

7. An internal combustion engine having a cam shaft, a cylinder valve, a source of high pressure uid, an actuating cylinder and piston for the valve, a line of communication between the actuating cylinder and the source of fiuid, said line having two branches, a follower cylinder' and piston in each branch, port means in each follower cylinder controlled by the follower piston, the port means being in the branches of the line of communication, and cam means on the cam shaft for actuating the follower pistons, the pistons being laterally disposed with respect to the cam shaft and one being advanced relative to the other in relation to the camshaft, the pistons being at a predetermined angle with respect to each other, the piston advanced relative to the direction of rotation of the camshaft being the valve closing piston and the other being the valve opening piston.

8. In a fluid system for controlling and actuating an engine valve, a source of high pressure fluid, an engine valve with an actuating cylinder and piston for opening the valve, a spring for closing it, a line of communication between the actuating cylinder and the source of fluid, said line having two branches, a follower cylinder and piston in each branch, port means in each follower cylinder controlled by the follower piston, the port means being in the branches of the line of communication, and a cam shaft with cam means for actuating the follower pistons, the pistons being disposed at a predetermined angle with respect to each other on the cam shaft so that one piston closes the Valve while the other opens it.

9. The structure of claim 8 in which at least one of the follower pistons is adjustably mounted so as to be movable in an arcuate direction with respect to the camshaft.

l0. The structure of claim l further characterized in that at least one of the follower cylinders and pistons is adjustably mounted so as to be movable.

ll. The structure of claim 2 further characterized in that at least one of the follower piste-ns is adjustably mounted so as to be movable to vary its time of actuation.

l2. In a hydraulic system, an engine valve, a piston therefore, a source of relatively high pressure fluid, a line of communication between the piston and the source having two branches, a follower cylinder and piston in each branch, independent of each other, and means for actuating the follower pistons so that their movements overlap substantially.

References Cited in the file of this patent UNITED STATES PATENTS 1,043,500 Bachrich Nov. 5, i912 1,810,465 Da Costa June 16, 1931 2,595,775 Wrangell May 6, 1952 2,602,434 Barnaby luly 8, 1952 FOREIGN PATENTS 573,596 France Mar. l3, 1924 

